Use of rechargeable batteries has increased substantially in recent years as global demand for technological products such as laptop computers, cellular phones, and other consumer electronic products has escalated. Current efforts to develop green technologies, such as electrical grid load-leveling devices and electrically powered vehicles, has further fueled the demand for rechargeable batteries having high energy densities.
One popular type of rechargeable battery is the lithium ion battery. Compared to other types of rechargeable batteries, lithium ion batteries provide high energy densities, lose a minimal amount of charge when not in use, and do not exhibit memory effects. Due to these beneficial properties, lithium ion batteries have found use in transportation, back-up storage, defense, and aerospace applications.
Traditional lithium ion rechargeable batteries have employed liquid electrolytes, such as a lithium-salt electrolyte (e.g., LiPF6, LiBF4, or LiClO4) mixed with an organic solvent (e.g., alkyl carbonate). As the battery is discharged to produce electrons, the electrolyte provides a medium for ion flow between the electrodes, and the electrons flow between the electrodes through an external circuit.
Unfortunately, existing rechargeable batteries (e.g., lithium ion batteries) are incapable of operating safely over a wide range of temperatures of interest. The energy density of existing rechargeable batteries is also inadequate for many applications.
There is a need for rechargeable batteries that provide high energy densities and operate safely over a wide range of temperatures, when compared to existing rechargeable batteries, such as lithium ion batteries.